[ghshephard]

This is one of those daytime fantasies we all have while daydreaming. Except, even when I'm really fantasizing, I never actually dream of things as ludicrous as this press release talks about.

What is it about battery technology that seems to attract the nutty companies? You don't see claims like this about CPUs, Monitors, Network Cards, etc... It's always batteries for some reason.

And one of Carbon, Graphene, or Buckyballs always makes an appearance as well in these press releases. It would be nice to see a new material take the stage as the "10x faster to recharge, recyclable, energy dense, environmentally safe" battery technology that will solve all our problems.

[wpietri]

My theory: if you want something bad enough, somebody will come along and sell you something. It won't work, but they'll still sell it to you.

Sometimes it's pure scam, of course, but I think that's rare. Mainly it's people who are clue-deficient in some important way. They think it works. Or they think they can get it to work. Or, like many marketing people, they're used to trusting somebody else that it works. It's the tech world's version of the magnetic healing bracelet or the ear candle.

The reason nobody is out selling 20 GHz processors is that nobody really wants them. It'd be nice, sure, but we're all pretty happy with what we have. Our desire for something better isn't strong enough to override our sense for what's realistic.

[iliis]

Good point! Altough bad example with the CPU: I do want a 20 GHz one and so do a lot of others. But I can see if it works as advertised very quickly whereas you cannot really absolutely with ultimate certainty prove that this bracelet doesn't work...

[wpietri]

Interesting. You can test a battery's capacity, too, so I don't think that's exactly it. I also don't think the collective desire for faster CPUs is all that strong; look at how few people bother going to the lengths of, say, overclocking and watercooling, let alone more exotic approaches.

Maybe it's better expressed as a balance between desire and experience. We have a lot of experience with CPUs, and we've grown accustomed to their speed, so our collective desire is modest. But collective desire for better batteries is very strong, and our experience with them is modest. So it's much easier for somebody to say, "Miracle tech! Give me millions!" And somebody will.

[M2Ys4U]

>you cannot really absolutely with ultimate certainty prove that this bracelet doesn't work...

Sure you can. Double-blind randomised controlled trials.

[mnw21cam]

>Sure you can. Double-blind randomised controlled trials.

(p > 0.95)

[alisnic]

Imagine these batteries in Teslas, that will mean a full charge in about ~10 minutes, which could potentially make all gasoline cars lame.

[tormeh]

This. We have electric engines pinned down. All that's missing from unlimited application of energy is better batteries and better power generation.

Look at it this way: Human endeavor consists of intelligent application of energy to mass. One of the three elements are close to being made trivial! It's very easy to get excited about batteries and renewable energy!

[baq]

this is not that simple. the article claims that density is similar to lithium batteries, but it doesn't say what kind of density is it. the fact that it charges 20x as much may mean naught if it holds 1/20 energy per kg or per liter.

[StavrosK]

What do you mean "what kind of density"? "Similar to lithium batteries" means just that, if you have a lithium battery of a certain size, this will hold an amount of energy similar to that.

[marvin]

A 30% difference would still be classified as "similar", but this would still be a big deal since batteries are just borderline capable to provide electric cars with sufficient charge to be acceptable for most people. A battery that's 30% worse than the best current batteries would be unusable.

[selectodude]

A car that could charge in 5 minutes and go 200 miles would be as useful to me as my current car. It's a start.

[Tuna-Fish]

Energy density can be given in terms of mass or in terms of volume. In general, if a source of a new interesting battery technology does not describe which one they mean in a comparison, you can assume the worst, that is, that they are comparable to lithium-ion in joules/m^3 (at which lithium ion isn't actually that good).

[barrkel]

Direct quote from the article: This unique battery offers energy density comparable to a lithium ion battery

I have no idea about how credible its claims are.

[tormeh]

I meant about the space in general. Sorry about the confusion. I've edited my post.

[Tuna-Fish]

Except that you also have to move the electricity into the car, which is actually the limiting factor in Teslas today, not the batteries. So this wouldn't really help at all.

[lpmay]

From Tesla's website it looks like they take ~1 Hr to charge (1C rate). That would make me think they are limited by the maximum charge rate of the cells.

[mnw21cam]

On the contrary, it is limited by the size of the cable going from the electricity distribution grid to the side of the car. With a typical (not a high performance) car engine capable of generating 75kW of mechanical power or so and a typical wall socket (in the UK at least) capable of transferring 3kW (and the average house having a 24kW total limit), there's going to be a problem that can only be solved by upgrading the cabling and using special high power sockets.

[gkoz]

That's with a 120 kW charger. Can they increase the power 6 times? 720 kW per car?

[mark-r]

At some point the amount of copper needed to carry the current becomes heavier than the batteries themselves. 120kW is already outlandishly strong, at 120V it's 1000 amps!

[toomuchtodo]

Are Tesla Superchargers 3-phase 480V on the incoming side? It seems they would need to be to support 120kW charging.

[XorNot]

If you had batteries which could accept that (Li-Ion's don't like going above 3C I think) and had the kind of energy density being claimed then it would be a relatively trivial matter to use a larger bank of them to provide the peak capability to charge a smaller bank of them.

[danmaz74]

Source?

[marvin]

Just read up on any existing quick-charging technology. Tesla's superchargers are the world's highest-capacity quick charging at 130kW, 2x the nearest competitor (CHAdeMO). And this still requires ~one hour to give the battery a full charge. Let's say you want to be able to charge in six minutes. That would mean something on the order of 1.3MW of electric power. So let's say you have a small-ish refueling station like a contemporary gas station, with eight charging spots. To power these, you need to pull ten megawatts from somewhere. The current power grid isn't dimensioned for this kind of demand, especially since the demand is very transient.

Tesla is attempting to solve this by building a massive battery storage capacity into the chargers and then trickle charging these batteries when the charging bays are not in use, so this is by no means a problem that has been solved once and for all.

[snowwindwaves]

Distribution level voltage is anywhere from 4kv to 25 kv. Say it's 12. Typical partridge or linnet distribution conductor might do 200 A. P=sqrt(3)IV cos theta = 1.73 * 200 * 12000 * 0.9 = 3.7 mw.

So you are correct your average distribution feeder probably does not have capacity for a 10 mw service. I guess that's not much of a shock.

[CapitalistCartr]

In the United States the normal distribution voltage, prior to being stepped down for consumer use, 7.6kv phase to ground, 13.2 phase to phase. So yes, you're pretty close, except the 13.2 kv would be 3-phase. For heavy industrial use, 4.4 kv is common for actual end user equipment, but above that would be some pretty serious equipment for an end user. Larger transmission lines operate anywhere from 60kv on up to 1.1 million volts, so lots of power is possible, as long as you don't mind the brownouts.

[loceng]

AFAIK it currently takes ~20 minutes to half-charge a Tesla. 20x would mean charging fully in ~2 minutes - nearly as fast as the automatic option for replacing depleted batteries with fully charged ones.

[masklinn]

> 20x would mean charging fully in ~2 minutes

Charge profile is not linear in existing batteries. A supercharger is 40mn to 80% and 75mn to 100%.

[JoshTriplett]

> Charge profile is not linear in existing batteries. A supercharger is 40mn to 80% and 75mn to 100%.

Many people have a mental model of battery charging like a tank of gas or another fluid, in which the first 10% and the last 10% take the same amount of time and effort.

It seems like a better mental model of battery charging would be a pressurized container of a compressible gas: the more you put in, the more it takes to put the next bit in.

[danielweber]

How does a quick-charge affect the longevity of the batteries?

[mnw21cam]

Not sure for LiIon batteries.

However, back in the days of NiCad batteries, some formulations could cope with really fast charges - and in fact would behave better and last longer after a very fast charge than they would after a slow charge.

We're talking about shoving 20 amps into a C cell for five minutes here. You needed to carefully monitor the cell temperature - the charging process wouldn't generate much heat until the cell was nearly full, at which point nearly all the energy going in would convert to heat. 20 amps would heat a full C cell up very quickly indeed.

[mikeash]

I don't believe it's known yet. Battery longevity seems to involve a lot of trial and error, and there isn't much data.

As far as I've been able to gather (and I have no real special knowledge here and could be way off), the main problem with quick charging is that it heats the batteries a lot, since charging is not a 100% efficient process and any waste energy turns into heat. Heat is bad for batteries, so it could affect their life. However, Teslas have active temperature management for their batteries (both heating and cooling, as required) which should mitigate that.

[loceng]

Ah, good to know - thank you.

[cLeEOGPw]

Except that it doesn't take 10 minutes to fill a gas tank and you can go 1000 km with full, unlike Tesla.

[BillyMaize]

It's probably the fact that a huge leap in battery technology would make huge changes in both electric cars as well as being able to store solar power (and therefore allowing people to live off the grid). Faster computer hardware wouldn't have nearly the effect and I'm sure these companies want the biggest hype possible.

[Someone]

Not always:

http://en.wikipedia.org/wiki/Jan_Sloot

http://en.wikipedia.org/wiki/D-Wave_Systems#Controversy (not clear cut in Wikipedia's mind, but I think their editors are somewhat in denial)

[lectrick]

Because affordable, fast, dense, safe electrical energy storage is pretty much the biggest obstacle to moving many technologies forward.

[mikeash]

It is interesting to consider what could be done if somehow a battery were invented that could, say, store 1GWh of energy in a $1 rechargeable cell the size of a AA battery with 99.9% in/out efficiency and no danger of catastrophic failure.

Every car would be electric. Airplanes too. The idea of running a vehicle on gasoline would be as ludicrous as the idea of running them on steam is to us now.

The massive challenges of wind and solar energy would disappear. Transmission and varying supply/demand are trivially solved with storage.

In computing, the massive effort expended in the name of efficiency would become unnecessary. Multitask all the things all the time! You want your phone to spin the CPU 24/7 listening for swear words so it can record hilarious videos automatically? Go for it.

[lectrick]

Well, I think there is a physics limit there, and gasoline happens to be VERY energy-dense (unfortunately for us trying to get away from depending on that property of it), but yes, that is fun to speculate on

[mikeash]

Yes, my battery is pretty clearly beyond physics.

It should be possible in theory to match the energy density of gasoline. You'd need to come up with a battery chemistry which takes in oxygen when it discharges and produces oxygen when it charges. Effectively, reversible combustion (or fuel cells). It's a tough problem but I don't think there's anything that fundamentally prevents it in theory.

Going much beyond it probably requires a nuclear process. You can store energy in certain isotopes by bombarding them with x-rays or gamma rays of a precise frequency. Stored energy can then be released with a similar process. In theory, it's possible to build a battery that uses this approach. In practice... to call it a difficult engineering problem would be a severe understatement.

[lectrick]

Is combustible energy storage currently the densest known, short of nuclear power?

[aidenn0]

It depends on your definition of "dense"

[mikeash]

There's always room for improvement, but it's starting to get within range of the fundamental limits.

Fundamentally, non-nuclear energy storage is limited by the strength of chemical bonds. For combustion, you're taking chemical bonds of high potential energy, breaking them apart, and rearranging the atoms into molecules with chemical bonds of lower potential energy. The energy difference is the heat produced by the combustion. The situation is similar in batteries, but in addition to rearranging atoms, free electrons are also liberated or consumed, with the bond energy difference going into that. For something like a mechanical spring, the winding force distorts the chemical bonds without breaking them, treating them like extremely tiny springs, with the same principle of operation as the big one. In all cases, the chemical bond strength determines how much potential energy can be crammed into the system.

For example, Wikipedia claims that flywheel energy storage (a "battery" where you just spin a disc faster to put energy in, and use it to drive something to get energy out) tops out at about 400Wh/kg. Lithium-ion batteries top out around 250Wh/kg, somewhat similar. Gasoline has a vastly better energy density at around 12,000Wh/kg... but gasoline needs to react with oxygen to release that energy! In fact it needs to react in an approximately 4:1 ratio, so the total mass going into the reaction is 5x the mass of the gasoline alone, making for an energy density of about 2400Wh/kg. Still much higher than batteries, but not outlandishly higher. I believe the difference would be because it's much easier to turn strong chemical bonds with a lot of potential energy into heat than it is to turn it into electrical potential.

You can see how reacting with the air gets you a huge advantage when it comes to how much stuff you need to carry around with you to store any given quantity of energy. And you can also sort of see how they all end up hitting the same basic limitations in the end. If you want to go further, you need take advantage of a stronger force with more potential energy, like the strong nuclear force.

(Gravity would be another possibility. If you could store energy by raising and lowering the orbit of a heavy object orbiting close to the Sun, you could get a pretty high energy density. Or if you want to go more exotic, store energy in the rotation of a neutron star or black hole. These approaches, however, pose even more difficulty for adaptation to automobile propulsion than the nuclear option.)

[lotsofmangos]

What is it about battery technology that seems to attract the nutty companies?

This is a collaboration between an academic research department and a mining conglomerate, with the CTO being the guy who developed the nickel cobalt aluminum cathode for the lithium batteries they use in the Tesla and the Prius. I wouldn't call it nutty.

[Tuna-Fish]

Getting 10 times more power density than lithium-ion isn't hard. It's also not very interesting, as we have enough power density already. Now we need more energy density.

[jjoonathan]

Number of occurrences: "power density": 0 "energy density": 1

[Tuna-Fish]

"charges 20 times faster", which is also found in the title, is a statement about power density.

My post was a reply to the post that decried nutty battery companies. I just wanted to point out that 20x power density of lithium ion is something that's actually feasible and available today. It, however, isn't all that useful and if you have to sacrifice even a single percent of energy density for it you're better off with lithium-ion batteries.

[mnw21cam]

Indeed. And if you don't have enough power density to (for instance) absorb energy from regenerative braking and then accelerate out of a corner, you just add a large capacitor with a massive power density (but a low energy density).

[cLeEOGPw]

What about magnetic batteries that always slowly charges from Earth's magnetic field.

[outworlder]

Assuming that it were orders of magnitude stronger, how could that possibly work, physically speaking? I see no way, unless the field was changing (rotating?) or the battery were moving to begin with.

[kaybe]

Well, it is.. on geological timescales. And with sudden flips at that. The record is in the orientation of suitable partices at the divergent plate boundaries ('frozen' like that when the lava cooled), which also is an indicator for ocean floor spreading and plate tectonics. It's pretty awesome, actually. But as the sibling comment says, in addition to being slow it's far too weak as well.

edit: Here's an image, because it's so awesome: http://en.wikipedia.org/wiki/Vine%E2%80%93Matthews%E2%80%93M...

[vanderZwan]

It could exploit the earth's motion through the interplanetary magnetic field[0] to charge your batteries... reeeeeeaaaally... sloooooowly.

[0] http://en.wikipedia.org/wiki/Interplanetary_magnetic_field

[cLeEOGPw]

That was a joke example of battery I made up that sounds believable enough to generate traffic from sites like this...

[ema]

The earth's magnetic field is several orders of magnitude to weak for that. Look at how you can control a compass with a fridge magnet.